Traditionally, doors are hung on wooden door frames by inserting screws through hinges into the wood surrounding the door. Newer, industrial constructions, however, typically use metal door frames. The frames are often thin-walled and hollow, and thus do not have a solid background material for inserting a screw.
Typically, manufacturers use gussets behind a door frame for receiving the screws and supporting the hinge and door. These gussets usually comprise a small plate of metal which is thicker than the door frame and which has casted or machined in its side screw holes which match the pattern of screw holes on the hinges. The holes in the gusset are tapped to receive the screws holding the door hinge.
The door frames generally include an indentation (called "emboss indentation" in the art) for receiving the hinge from the door. A gusset is generally attached or held in place against the back of this emboss indentation, before the frame is attached, by some form of tab, which is inserted into the gusset when the gusset is in place. Holes are included in the emboss indentation which match the screw hole pattern on the hinge and the gusset and which are aligned with the screw holes on the gusset when the gusset is placed on the tabs. After the gusset is in place, the door frame is attached to the wall. The door frame then stands ready for the attachment of a door, which simply requires inserting a screw through the hinge, through the hole in the door frame, and into the gusset.
The problem with the gusset systems of the prior art is that several manufacturers, including the assignee of the present application, each use different hole patterns for their hinges and gussets. Thus, the gussets, emboss indentations, and hinges must have matching patterns for the holes. If a contractor works with several different manufacturers, he must carry a variety of different door frames, in addition to a large quantity of different gussets. Although stocking several gussets is generally not that much of a problem, the size and weight of door frames makes stocking a large number of door frames inconvenient and costly.